The problem comes along this path.

For a middle class person, the major problems are not enough money... so, the govern-cement solution is to throw money at it.

However, the poor are not helped by money.
They actually need things. They need tools to become self sufficient.

Our society is geared to take those tools away from people.
Land? Didn't make enough money, say goodbye to your land.
Growing your own food... well, not in this spot, or that spot, or like that, or...

Basically, the govern-cement has made the minimum level of competence need to live a fruitful life at over 100 IQ. Thus, half of the people are outlawed from having a fruitful life.

This is what needs to change, not money.

And, if we really cared about the poor, what we would give them is a tiny house on a piece of land.
This would cost far less than any UBI.